1. Field of the Invention
The present invention relates to a memory card designed for reception in a memory card receptacle and into or from which information signal is to be written or read, and the memory card receptacle.
2. Description of Related Art
A well-known memory card incorporating memory chips in which information signals are stored is provided with terminals which are to electrically be connected with an external system. The memory card is supplied with a voltage through the terminals and also delivers and receives information signal to and from the internal memory chips through the terminals.
Since the terminals for connection of the memory card to an external system are also electrically connected to the internal memory chips, they should be protected from being touched when the memory card is used. More particularly, if the terminals are directly touched, a static electricity will take place in them, which however is a rare case, and be carried from the terminals to the memory chips which thus will possibly be broken down. To avoid this, the terminals should be protected against easy access to them from outside to prevent such a breakdown due to a static electricity.
Also, the memory card of this type is featured by its transportability. So, it has been tried to design more compact memory cards for the convenience of portability. Thus, along with the more compact design of the memory card itself, its terminals have been designed thinner and arranged at reduced intervals.
Such thin, closely disposed terminals for connection an external system will possibly be deformed and broken even if just lightly touched.
To prevent the terminals from being deformed or broken down, a memory card of this type has been proposed in which such terminals are buried inside in the memory card body and small holes communicating with the terminals are formed in the memory card body so that the terminals are exposed to outside only through the holes, or in which a concavity is formed in a forward end portion of the memory card body in the card inserting direction and terminals are disposed in the bottom of the concavity for protection of them.
However, the memory card in which the small holes are formed in the card body for the terminals to be exposed to outside is hard to disconnect from the receptacle if the holes are clogged with dust or the like. When the memory card is inserted into the receptacle with the holes left clogged with dust, no positive connection with the receptacle can be attained and also the terminals of the receptacle may possibly be deformed as the case may be.
Further, the above memory card is apt to have a complicated structure and is manufactured with large costs. Therefore, the conventional memory card is not suitable for mass production.
Also, in the memory card having formed in the body thereof the concavity in which the terminals are disposed, the protection of the terminals cannot be protected to a satisfactory extent if the concavity is improperly shaped. If the concavity is not shaped for a satisfactory protection of the terminals, dust or the like is likely to heap or stay in the corners of the concavity and block the terminals of the memory card from secure connection with those of the receptacle.
Further a memory card has been proposed which is cut at one of the corners of a generally rectangular body thereof to prevent the memory card from being inserted incorrectly (in a wrong direction or posture) into a memory card receptacle. In this case, however, the memory card cannot be designed to have a variety of shapes by chamfering or rounding, for example, the other three corners.